I am by far no SonarCloud expert, but I’d like to point out that my own open topic (linked) exhibits exactly the same behaviour of SonarCloud, with the value of sonar.test.inclusions being appended into sonar.exclusions right after **/build-wrapper-dump.json,[original contents of sonar.exclusions],..., and as far as we can detect - we are not overriding those settings anywhere. So it may be that the OP also doesn’t, and that SonarCloud’s own code is doing it for a reason we haven’t figured out yet - either as a feature we can’t find documentation for, or as a bug.
See text comparison screenshot in my own topic (in the original post).
I also find it interesting that the OP and we are using a different CI system (Azure DevOps) and a different scanner (Azure DevOps extension), which could likely mean that this behaviour originates from the core of SonarCloud, and could therefore potentially affect more users.